I. FIELD OF THE INVENTION
This invention relates to a hinged member for a rear impact guard and, more particularly, a hinged member for a rear impact guard for use with a liftgate on the rear of a semi trailer.
II. DESCRIPTION OF THE RELATED ART
The present invention contemplates a new and improved rear impact guard; a system including a rear impact guard, a liftgate, a hinged member; and a device adaptable for use with a rear impact guard, all for use with a vehicle such as a semi-trailer truck. The present invention is simple in design, effective in use, and overcomes the foregoing difficulties and others while providing better and more advantageous overall results.
The present invention relates to a bumper for a truck providing underride protection. The semi-trailers are elevated to a level whereby a typical automobile can pass under the trailer frame. Therefore, where the automobile collides with the rear of the semi-trailer the front end of the automobile travels under and below the semi-trailer. The height of the semi-trailer is such that the windshield of the automobile is the first element of the automobile to contact the semi-trailer. Thus, upon impact of the automobile with the semi-trailer great injury results. To minimize and/or eliminate the ability of the vehicles to travel under the semi-trailer trucks have a rear impact guard mounted to the rear of the semi-trailer. The rear impact guard is typically mounted under the semi-trailer. Various prior art patents disclose a rear impact guard mounted to the underside of the semi-trailer. For example, U.S. Pat. No. 5,507,546 entitled UNDERRIDE PROTECTION BUMPER discloses a vehicle bumper which provides protection against other vehicles underriding the vehicle. The bumper structure has a pivoting arrangement and breakable links. The bumper protector is designed such that upon collision of a vehicle with the bumper protector the pivoting of the bumper lifts the rear of the truck being hit and smashes downwardly on the front end of the impinging vehicle thus not allow the impinging vehicle to travel under the semi-trailer.
Other types of rear impact guards are disclosed within the prior art aiming to absorb the shock between the impact of the vehicle against the rear impact guard. U.S. Pat. No. 4,247,138 entitled SHOCK ABSORBING APPARATUS FOR VEHICLES discloses a rear impact guard having a shock absorbing device. The shock-absorbing device allows the arm of the rear impact guard to deflect toward the front of the semi-trailer truck thus absorbing some of the impact of the collision.
A yet further rear impact guard is disclosed within U.S. Pat. No. 5,673,953 entitled BREAKAWAY ICC BUMPER. The patent discloses a movable bumper having a one-way hinged connection with biasing springs with pulley/cable connectors. This invention is aimed at dealing with a slightly different problem of rear impact guards. Due to the nature of the rear impact guard being mounted below the underside of the semi-trailer roadside obstructions contact these impact guards with considerable force. Thus, the impact guard and the vehicle are damaged. For example, a dip in the road can cause the impact guard to impact the road, thus causing damage to the impact guard. To deal with this problem, U.S. Pat. No. 5,673,953 discloses utilizing a hinged connection which is biased in one direction by transversally mounted tension springs. Thus, when an obstruction contacts the bumpers bottom portion it moves at its upper hinged area against the biasing action of the springs and attached pulley link. This causes the bumper's lower end to move outwardly away from the vehicle.
Trucks subject to the jurisdiction of the U.S. Interstate Commerce Commission (ICC) currently have regulations for the rear impact guards. A relatively new regulation requires that the rear impact guard be mounted no greater than twelve inches (12') (305 mm) from the rear of the trailer extremity. This regulation presents a problem to those trucks utilizing a liftgate. Powered liftgate systems have been in use for many years. These liftgates are mounted on the rear of the truck, and more specifically, as close to the rear of the semi-trailer as possible. The liftgate aids the operator in shipping and receiving articles and loading articles within the semi-trailer. With the regulations that the rear impact guard be within twelve inches (12') (305 mm) of the rear extremity of the trailer, a problem arises with the operation of the liftgate.
In operation, the liftgate travels in an up and down vertical direction. The operator operates the liftgate utilizing a motorized system. The liftgate has a travel range from the road to the bed or inside of the semi-trailer. Therefore, when loading heavy items these items can be loaded from the road directly onto the liftgate platform which is parallel and contacts the surface of the road. The liftgate then operates in an upwardly vertical direction to at least a level parallel with the bed of the trailer. The item is then moved from the platform of the liftgate to within the bed of the semi-trailer thus providing an efficient manner of loading an item. At the receiving end, the reverse steps are taken to unload the item it the same manner as loading the item.
The travel of the liftgate in this upwardly and downwardly vertical direction presents a clearance difficulty in the travel of the liftgate with respect to the rear impact guard. Upon traveling in its upwardly and downwardly vertical direction, the liftgate impacts the rear impact guard thus impinging its travel.
The main object of the present invention is to overcome the aforementioned difficulty of using a liftgate with a rear impact guard.